But in February Mr Trump took to Twitter to condemn the agreement. "Do you believe it? The Obama Administration agreed to take thousands of illegal immigrants from Australia. Why? I will study this dumb deal!" he tweeted.

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Speaking after today's meeting, Mr Trump lauded the United State's alliance with Australia, pointing out that the two countries have been "allies for 99 years".

Both leaders also addressed the importance of the US-Australia alliance during the Battle of the Coral Sea.

"It was the turning point of the war," Mr Turnbull said.

While the Japanese decided not to invade the Australian mainland during World War II, it aimed to cut Australia’s supply lines from the US.

In 1942, Allied troops halted the Japanese from advancing into the Pacific by launching airborne attacks.

The Japanese were defeated when the US sank four Japnese aircraft carriers about a month later.

It was the largest naval battle to be fought so close to Australia.

Mr Turnbull also said the two leaders shared similar challenges, such as passing legislation through parliament.

Watch: Turnbull and Trump at Coral Sea dinner

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'We really love Australia': Battle of the Coral Sea anniversary

Mr Trump was full of praise for Australia during his address at the 75th anniversary of the Battle of the Coral Sea, reaffirming the relationship between the two countries.

“We renew our old friendship and we pledge our lasting partnership in the search for prosperity and ever lasting peace,” he said.

He thanked for its alliance from the historic battle to the recent fight against terrorism in Syria, Iraq and Afghanistan.

“Americans have had no better friends than the Australian, I mean that,” Mr Trump said.

“On behalf of the United States, I thank the Australian people tonight. Believe me, I have so many friends here from this country.

“We love Australia, all of us, we really love Australia.”

The sentiment was echoed by Mr Turnbull, who too reflected on the importance of the US-Australia alliance through the past two Centuries.

“From the battlefield of Fromelles nearly 100 years ago to our forces fighting side by side in the Middle East at this very moment, and as we reflect on the Battle of the Coral Sea, we are reminded of how the stability and prosperity of our region over so many decades has been secured and is secure today by the United States.”

He restated the two countries condemnation of North Korea's “reckless provocation”, and paid tribute to Australians and Americans who have served in the countries defence forces.

“We honour you, we thank you.”

Watch: Trump compares US healthcare to Australia

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Earlier Mr Trump chose to delay and change the venue of the meeting with Mr Turnbull.

The leaders were scheduled to meet at Manhattan's Peninsula Hotel at 4pm on Thursday (6am AEST Friday).

With the US House of Representatives voting on a bill in Washington DC to replace Obamacare, and Mr Trump heavily involved in lobbying to get enough votes for it to succeed, the meeting with Mr Turnbull was pushed back to 7.15pm (9.15am AEST).

It was held on the decommissioned USS Intrepid aircraft carrier docked on the Hudson River as part of the Intrepid Sea, Air and Space Museum.

The aircraft carrier is also the venue for the event to honour the 75th Battle of the Coral Sea anniversary, with both Mr Trump and Mr Turnbull due to deliver speeches.

More than 700 guests, including four Australian and three American veterans of the battle aged in their 90s, will attend.

Mr Turnbull had a busy morning in Manhattan. The prime minister received a tour of the NYPD's state-of-the-art Joint Terrorism Taskforce and operations centre.

The facility is about the size of an indoor basketball court and features hundreds of video screens linked to around 10,000 law enforcement, government and private video cameras across New York.

It will be the security nerve centre for Mr Trump's New York visit on Thursday afternoon.

Mr Turnbull then walked several blocks on public streets, surrounded by a ring of Secret Service officers, to a meeting with Admiral Harry Harris, commander of US Pacific Command.